This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 18 |
| 2 | 245 |
| 3 | 3135 |
| 4 | 40369 |
| 5 | 537628 |
| 6 | 7494416 |
| 7 | 109911300 |
| 8 | 1698920916 |
| 9 | 27679825272 |
| 10 | 474957547272 |
| 11 | 8572072384512 |
| 12 | 162478082312064 |
| 13 | 3229079010579072 |
| 14 | 67177961946534528 |
| 15 | 1460629706845766400 |
| 16 | 33139181950164806400 |
| 17 | 783398920650352012800 |
| 18 | 19268391564147377318400 |